JLH Headphone Amp - Page 26 - diyAudio
Go Back   Home > Forums > Amplifiers > Headphone Systems

Headphone Systems Everything to do with Headphones

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 21st August 2012, 02:04 PM   #251
diyAudio Member
 
robertor's Avatar
 
Join Date: Nov 2007
Send a message via Skype™ to robertor
thanks, I will study.
__________________
rob
  Reply With Quote
Old 14th September 2012, 11:11 PM   #252
Jean is offline Jean  United States
diyAudio Member
 
Jean's Avatar
 
Join Date: Mar 2002
Location: Sacramento, CA
Send a message via AIM to Jean
Ordered the board
__________________
left lane is for passing, slower traffic keep right please.

Last edited by Jean; 14th September 2012 at 11:17 PM.
  Reply With Quote
Old 15th September 2012, 01:34 AM   #253
Jean is offline Jean  United States
diyAudio Member
 
Jean's Avatar
 
Join Date: Mar 2002
Location: Sacramento, CA
Send a message via AIM to Jean
Can someone point me to a BOM for the eBay board? thanks !
__________________
left lane is for passing, slower traffic keep right please.
  Reply With Quote
Old 15th September 2012, 02:16 AM   #254
diyAudio Member
 
ashok's Avatar
 
Join Date: Jun 2002
Location: 3RS
Jean, you must have deleted your post asking about the supplier of my JLH board. I did get the message by email !

Your problem appears to have been solved. In any case, I made my own board, which isn't great. Been planning to update it as soon as I have time but want to add a protection circuit ( relay) so that just in case there is a large dc offset it shouldn't fry my expensive phones. I run my amp on +/- 12 volts and it sounds very good. The supply is regulated by LM7812/LM7912 chips.

I notice many people having severe offset on power on and the offset settling down after some time. I will check this on my amp which is a straightforward implementation of the JLH circuit. The heat sink size is critical to keep the temperature down and reduce drift. I remember seeing only low offset voltages on it. But I could be wrong.
Cheers.
__________________
AM

Last edited by ashok; 15th September 2012 at 02:19 AM.
  Reply With Quote
Old 15th September 2012, 03:17 AM   #255
Jean is offline Jean  United States
diyAudio Member
 
Jean's Avatar
 
Join Date: Mar 2002
Location: Sacramento, CA
Send a message via AIM to Jean
Hi, yes I just scanned through the thread and board the bare board on eBay. I think I can come up with the BOM using Miles posts, but need to know what heatsinks to order that will fit the board exactly.

I use Sony MDR-7506s as my headphones, hopefully this will satisfy me, but it is my first dedicated headphone amp. My main amp is a diy p3a based dual mono, powering my diy scanspeak 3 ways.
__________________
left lane is for passing, slower traffic keep right please.
  Reply With Quote
Old 15th September 2012, 06:18 AM   #256
oz7aff is offline oz7aff  Denmark
diyAudio Member
 
oz7aff's Avatar
 
Join Date: May 2012
Location: Denmark
Quote:
Originally Posted by Jean View Post
Hi, yes I just scanned through the thread and board the bare board on eBay. I think I can come up with the BOM using Miles posts, but need to know what heatsinks to order that will fit the board exactly.
This is the heat sinks that I have used:
12pcs Transistors TO-220 Aluminum Heat Sink | eBay

I have no BOM, but a checklist

220p
330p
0u1
2u2
100u
2200u
2V7
4007
4148
LED
7812
7912
KLEM3
CON3
KLEM2
10K TPOT
10k Vol POT
2R2
5R1
22R
100R
470R
1k
2k2
3k3
4k7
220k
2N2222
2N2907
TIP41
Heat Sink
  Reply With Quote
Old 15th September 2012, 11:00 AM   #257
hotiron is offline hotiron  Scotland
diyAudio Member
 
hotiron's Avatar
 
Join Date: Feb 2007
Location: Aberdeen Scotland
NEW Ver JHL Class A Headphone amplifier PRE AMP KIT DIY | eBay

Just buy the board ready built Jean. Save you a lot of hassle!
__________________
If you give up easily Dont start!!
  Reply With Quote
Old 15th September 2012, 11:19 AM   #258
diyAudio Member
 
Join Date: Dec 2011
Default Ebay JHL Headphone amp

Agree with Hotiron, far easier to buy fully assembled and tested board then remove/replace the half dozen components to make it sound great.
Best $30 i ever spent, after a few modifications of course. Recommend you keep the DC output offset bias circuit, but you need good filtering to avoid hum coupling into your input stage transistor. Follow the thread, all the information is there. Good luck with your build. Post some pics.
  Reply With Quote
Old 15th September 2012, 12:28 PM   #259
diyAudio Member
 
ashok's Avatar
 
Join Date: Jun 2002
Location: 3RS
The board linked by Hotiron looks nice. But the input cap is questionable. This can affect the sound if it isn't good. You could start with it and see if other film caps are better. However they might not fit on the board and could be placed near the input RCA sockets.
At least it is some place too start !
My board just has a long heat sink ( plain 1.5 mm aluminum strip) on each side of the board. I wanted to make the new board so that it can sit directly on one finned heatsink. Need to find that heatsink first !
__________________
AM
  Reply With Quote
Old 15th September 2012, 01:50 PM   #260
hotiron is offline hotiron  Scotland
diyAudio Member
 
hotiron's Avatar
 
Join Date: Feb 2007
Location: Aberdeen Scotland
I use a Wima 2u2 "MKS2" at the input, no bypass. Sounds good. The feedback cap has a huge influence on the sound also I have 220uF Elna silmics in there.
__________________
If you give up easily Dont start!!
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
JLH headphone amplifier steveh49 Headphone Systems 8 14th May 2014 03:31 PM
JLH Headphone amp aethelbert Headphone Systems 4 13th July 2009 11:14 PM
JLH headphone amp with FET's and servo nelsonvandal Headphone Systems 17 30th August 2008 09:26 PM
PCB for JLH amp FaTTy Solid State 0 27th March 2007 04:40 PM


New To Site? Need Help?

All times are GMT. The time now is 04:15 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2